Abstract.This article is motivated by the importance of building web data mashups. Building on the remarkable success of Web 2.0 mashups, and specially Yahoo Pipes, we generalize the idea of mashups and regard the Internet as a database. Each internet data source is seen as a table, and a mashup is seen as a query on these tables. We assume that web data sources are represented in RDF, and SPARQL is the query language. We propose a query-by-diagram language called MashQL. The goal is to allow people to build data mashups diagrammatically. In the background, MashQL queries are translated into and executed as SPARQL queries. The novelty of MashQL is that it allows querying a data source without any prior understanding of the schema or the structure of this source. Users also do not need any knowledge about RDF/SPARQL to get started.